Epidermal cooling has been determined to allow higher fluences and reduce pain and side effects, especially in darker skin. Three types of cooling have been developed:
Contact cooling: through a window cooled by circulating water or other internal coolant. This type of cooling is by far the most efficient method of keeping the epidermis protected since it provides a constant heat sink at the skin surface. Sapphire windows are much more conductive than quartz.
Cryogen spray: sprayed directly onto the skin immediately before and/or after the laser pulse
Air cooling: forced cold air at -34 °C